1. Field of the Invention
The invention relates to a load carrying lifting sling of the type formed of a high tensile strength strap or webbing composed of textile yarns which lie next to one another in approximately the same plane in the longitudinal direction of the webbing, which are held together in their juxtaposed position and which are made, in particular, of synthetic material, and with the lifting sling being provided with lifting loops for the attachment of a lifting device (8), and tie loops for fixing a load to be lifted, with each lifting loop lying next to a respective tie loop and being separated by division of the textile yarns into two parallel strands of webbing which are separated from one another by a slit extending in the longitudinal direction of the webbing. A load carrying lifting sling of this type is disclosed, for example in British Patent No. 1,556,818.
2. Discussion of the Prior Art Lifting slings of the above type, also sometimes called "cloverleaf" slings, are traditionally composed of a textile webbing. Such textile webbing can be woven in a practically unlimited length which is limited only by transporting possibilities. Lifting slings of different circumferential lengths are required for the respective uses. To produce such slings of textile webbing, the webbing is cut to the desired length from an available supply and the two ends of the piece of webbing are sewn together. Such a cloverleaf sling has been further developed by sewing on or otherwise attaching tie loops likewise composed of textile webbing material, as shown, for example, in DE-AS No. 2,256,452 which corresponds to U.S. Pat. No. 3,701,559.
Since the sewing of tie loops to lifting straps, which are likewise composed of textile webbing material, is very labor intensive, a lifting sling with tie loops as described above and disclosed in British Pat. No. 1,556,818 has been developed in which the load carrying means, instead of textile webbing, is a single or multi-layer skein of yarns, with the textile yarns forming a closed ring-shaped strap. The transverse connection of the threads in the skein is effected by an elastic, moisture resistant binder, namely a layer of plastic. The drawback of these lifting slings with tie loops, which can be produced with savings of labor and costs, is that, depending on the machinery employed by the manufacturer, they can be produced only to a limited circumferential length. Such lifting slings can also not be produced with any desired load carrying capability because the thickness of the plastic layer producing the transverse bond between the textile yarns is limited by the need to ensure a minumum degree of flexibility for the lifting sling. A further drawback of these lifting slings is also that the user can obtain them only in lengths determined by the manufacturer.